Why is it so unsettling that Luke Kuechly cried? This is a sport where players suffer brain injuries every single game, yet Kuechly’s apparent concussion and subsequent reaction as he was carted off the field has completely overshadowed the Panthers’ win, in a way that doesn’t happen when someone is merely knocked unconscious, or even taken off on a spinal board. That football players are physically vulnerable is no surprise, but but psychological vulnerability is rarer to see, and that much more disturbing.

There’s no official word this morning on the 25-year-old linebacker, who the Panthers said last night was being evaluated for a concussion. I think brain trauma is a safe bet:

“It’s hard,” Greg Olsen said. “It’s one of your buddies, it’s one of your guys pretty shaken up. There’s no real words to really describe it. It all comes down to you just hope he’s OK. It’s really all we can do.”

Kuechly, one of the best defensive players in all of football, missed three games with concussion symptoms last year after a play that looked a lot like this one, minus the emotional aftermath. And while it’s always scary and terrible to see any athlete get hurt—especially knowing what we’re starting to learn about the long-term effects of brain injuries—there is undeniably something different about this one.

Of course, the difference is Kuechly’s tears. In the best-case scenario (and it’s still awful), here was a huge, talented, peak-health, full-grown man weeping in fear. Fear of being betrayed by his brain, trying to regain his breath and his balance after taking a hit that temporarily took away an athlete’s greatest gift: control of his own body. Fear of what this and other concussions will mean for his abilities and quality of life, this year, next year, 10 years from now, 30 years from now. In a worst-case scenario, those tears weren’t the product not of contemplation but of a brain so scrambled it couldn’t control itself. Pseudobulbar affect is a condition that can follow concussions in a minority of patients. Also called emotional incontinence, it involves uncontrollable crying (or, perhaps even more horrifically, laughing) after a traumatic brain injury. The mechanisms aren’t perfectly understood, but they’re believed to result from a disruption of the neural networks that regulate emotion. Tears, in some instances, are every bit the visual indicator as the fencing response that something has gone horribly wrong in the brain.

Kuechly’s cart ride was particularly difficult to watch because most of the time, physical symptoms and emotional pain (which can be the same thing) occur later, off-camera, where we don’t have to see it, where it may as well not exist for it. I’ve written this before, but it bears repeating: Football fans like me can generally accept the human toll of this sport right up until the moment we’re forced to think about it.